The present invention relates generally to fuel-fired heating apparatus, such as fuel-fired air heating furnaces, and more particularly relates to specially designed fuel/air mixing and combustion sections of such fuel-fired heating apparatus.
In fuel-fired heating appliances such as, for example, furnaces, a known firing method is to flow a fuel/air mixture into a burner box structure in which a suitable ignition device is disposed to combust the fuel/air mixture and thereby create hot combustion gases used to heat air (or another fluid as the case may be) for delivery to a location served by the heating appliance. The hot combustion gases are flowed through a series of heat exchanger tubes, externally across which the fluid to be heated is flowed, and then discharged from the heating appliance into a suitable flue structure. Due to various configurational characteristics of the heating appliance, during firing of the appliance undesirable uneven heating of the combustion product-receiving heat exchanger tubes may occur such that an undesirable non-uniform temperature distribution is present in the overall heat exchanger tube array.
In addition to this potential heat exchange unevenness problem, other problems that may arise in the design of fuel-fired heating appliances include an undesirable noise level generated in the creation of the fuel/air mixture delivered to the burner box, an undesirably low level of mixing of the fuel and air, and an undesirably high level of NOx generated in the fuel/air mixture combustion process.
As can be seen, a need exists for alleviating the above-noted problems associated with conventional fuel-fired heating appliances of various types. It is to this need that the present invention is primarily directed.